Diablo 1 HD Hellfire Mod | Awake

I went to Diablo and used the lower res skill and got half of his life blown away.
after that i left for a safe area and waited for over a minute to get the lower res skill again. i went back to diablo and he got full life. is that normal?

Yes. If you deagro monster his health will go up rapidly or even reset combat.

thanks for the answer. nice feature